Education Secretary Ruth Kelly last night warned parents they must back headteachers over discipline, after a teaching union demanded compulsory parenting classes for everyone.

Speaking to The Birmingham Post, Mrs Kelly said parents needed to play a role in schools in order to raise standards. But she said most parents already wanted to help their children.

The National Union of Teachers claimed this week that the emphasis on eradicating ill-discipline should be on parents, not teachers.

Nigel Baker, deputy general secretary of the Birmingham NUT branch, called for parenting classes to be provided for every mother and father.

It followed a report by education watchdog Ofsted which found bad behaviour, including drug-taking, weapons, and gang culture, was a problem in as many as half of all schools.

Speaking after the launch of Labour's thirdterm education policies, Mrs Kelly said: "Parents want to be helpful and want to support their children. Now, parents have rights.

"They have the right for their child's individual needs to be taken seriously, good standards of behaviour in the classroom, and good teaching in modern school buildings.

"And they also have responsibilities. I think that we really need to make it clear that we back heads in their judgment and that parents have a responsibility to back heads in school discipline.

"To take what is happening in Birmingham, the local authority is one of the first authorities in the country to have taken up the new powers we have through the anti-social behaviour legislation to issue fixed penalty notices when there is an attendance problem.

"Birmingham issued 800 warning letters. In fact, attendance improved so dramatically that they only had to issue 24 fixed penalty notices out of those 800.

"It's really important that there are responsibilities as well as rights on parents."